( 7587 of 7587 ) |
United States Patent | 3,567,935 |
Nagel | March 2, 1971 |
An earth formation porosity logging tool in accordance with an illustrative embodiment of the invention comprises a neutron source and four neutron detectors spaced at different distances from the source for transport through a borehole. Signals are obtained that correspond to the ratios of the counts registered by the two short-spaced detectors and the two long-spaced detectors. The effect of the borehole on the formation porosity measurement is compensated by combining these ration signals to eliminate the influence of the borehole neutron relaxation length and converting the resultant signal into an output signal that more accurately indicates the formation porosity.
Inventors: | Nagel; Walter A. (Houston, TX) |
Assignee: |
Schumberger Technology Corporation
(New York,
NY)
|
Appl. No.: | 04/703,678 |
Filed: | February 7, 1968 |
Current U.S. Class: | 250/264 ; 250/266 |
Current International Class: | G01V 5/00 (20060101); G01V 5/10 (20060101); G01t 003/00 (); G01v 005/00 () |
Field of Search: | 250/83.6 (W)/ 250/83.1,71.5,83.3 |
3462600 | August 1969 | Dewan |
2469462 | May 1949 | Russell |
2776378 | January 1957 | Youmans |
3413466 | November 1968 | Allen Jr. |
3435217 | March 1969 | Givens |
Tinch et al., "Computer Application," June 1966, p 687--696, 83.6W. |